1.1. Lisp Dialects

Any language that obeys the central principles of Lisp is considered a Lisp dialect. Since these principles are so simple, it’s not surprising that literally hundreds of dialects of Lisp have been created. In fact, since so many budding Lispers create their own Lisp dialect as an exercise, there may be thousands of partially completed Lisps slumbering in long-abandoned directories on hard drives across the planet. However, the vast majority of the Lisp community uses two Lisps: ANSI Common Lisp (often abbreviated CL) and Scheme.

In this book, we’ll be talking exclusively about the ANSI Common Lisp dialect, the slightly more popular of the two. Nevertheless, most of the knowledge you’ll gain from reading this book will also be relevant to Scheme (although the names of functions tend to differ somewhat between the dialects).